FRANKFURT, Germany {AP} Striking Lufthansa pilots grounded hundreds of flights at the continent's largest airport Thursday, but the airline dodged the chaos of last week's warm-up strike by rebooking thousands of international and domestic passengers on alternative airlines and even trains.

By late morning, Lufthansa had canceled 508 of its 1,100 flights departing Germany  affecting tens of thousands of passengers at its hub airport in Frankfurt alone. More cancellations were possible, Germany's largest airline warned.

Lufthansa countered Thursday's 24-hour action by frantically rebooking passengers on other flights, including those of competing airlines. It also tried to soothe frayed nerves by serving free sandwiches and drinks to those mired in snaking check-in lines.

"I was a little frustrated to learn that my flight was canceled this morning," said Mark Bartholomew, a 26-year-old U.S. soldier waiting to get rebooked on a flight to Minneapolis. "I think this is the last line I have to wait in before I get my ticket and have to wait in another line."

But the mood at Frankfurt appeared less tense than during last week's half-day strike when hundreds of frustrated passengers camped out on suitcases in the airport lobby. This time, many customers were aware beforehand of the planned walkout.

Still, check-in lines were much longer than usual and the big departure board showed delays for many of the flights still operating. The airline urged affected passengers to take trains.

Lufthansa pilots are demanding a 30 to 35 percent pay raise, saying they have fallen that far behind average industry wage levels. In return, Lufthansa has offered pilots a 26 percent wage increase in 2001, the first of a four-year package. Pay raises in the other years would be based on inflation and profit-sharing.

Pilots rejected the offer Wednesday and broke off talks, saying a four-year contract dilutes the overall raise to just over 2 percent a year because the profit-sharing and inflation components couldn't be guaranteed.

"If you want to call a strike a success, then this is one," Georg Fongern, spokesman for the pilot union Vereinigung Cockpit, said Thursday. "This is a sign to Lufthansa that we must resume talks as soon as possible."

The airline has blasted the strike as "irresponsible." Analysts estimate Thursday's 24-hour action alone will cost Lufthansa up to $22 million. Lufthansa had no immediate estimate.

Last month, Lufthansa said first-quarter operating profit plunged 94 percent and hinged its recovery on wrapping up pay talks with pilots quickly.

News of the strike sent the company's shares down 2 percent Wednesday. In trading Thursday, though, shares were up 0.6 percent at 21.91 euros ($19.50) in Frankfurt trading.

Pilots have pledged to have 24-hour strikes every Thursday until an agreement is struck, and have threatened to step up the walkouts if progress isn't made soon. Fongern said he hoped both sides would resume negotiations Friday or Saturday, though no new talks have been scheduled.